Here's my take on Bernie: he's the only candidate in the race (even though he hasn't declared himself as running yet) who presents a threat to the Democratic party establishment, as evidenced by their attitude and behavior towards him and his supporters. This is entirely a good thing that needs to happen, and the sooner it does, the better.
He is the only candidate who does not get huge donations from big banks and corporations, which means they would rather have someone else as president. We need to interpret this as the fucking fluorescent blinking neon sign of a point in his favor that it clearly is.
He is the only candidate who is not in favor of endless war overseas. Most Democrats are against wars that Republicans wage, or are against wars that hurt "American interests" on those grounds alone, and will not hesitate to endorse the philosophy of a paternal United States doling out its democracy to the world via smiling drones and perpetual troop presence.
He energized a movement that has put Medicare for all on everybody's lips; we're on the cusp of that being a litmus test for a candidate (as it should be), when just two years ago Hillary announced to roaring applause that it would "never, ever happen". As the other candidates begin to fall in line with weasely pronouncements about "affordable access to health insurance for all", Bernie is still clearly and resolutely campaigning on health care for everyone. Free university education means free university education when he says it, not free for the first two years as long as it's a community college (and nothing to prevent them from simply doubling the price of the next couple of years to make up for the difference). He has helped make a $15 minimum wage a national topic of conversation, which contributed to pressuring Amazon to initiate it as a policy.
Bernie is a social democrat, like AOC, not a socialist, but he calls himself a democratic socialist anyway. This bothers me slightly, but in any case Bernie is the closest thing to an actual socialist by a huge margin. Everyone seems to think that the socialist label is enough to sink him, but year after year, it's becoming more and more palatable to voters--especially Democrats, who favor socialism and capitalism about equally. Just one presidential term ago, this would have been unfathomable. Today, Bernie is the most popular politician in the country as an avowed socialist, and AOC is probably not far behind. The party is shifting to the left, whether the establishment likes it or not.
He is the only candidate who doesn't have to be given some kind of a pass to explain his behavior before he ran for President. Kamala Harris has her gross authoritarian actions as district attorney and "top cop". Beto O'Rourke votes to the right of every candidate in the running and couldn't beat a blobfish with no conscience. Tulsi Gabbard made unfortunate comments about gay marriage, abortion, and Islam that garnered her the support of Steve Bannon, who wanted Trump to install her as secretary of state. Elizabeth Warren was a Republican until not too long ago, and is committed above all else to keeping market capitalism running smoothly. Joe Biden will be instantly torpedoed into irrelevance when (not if) somebody #metoo's him. The first thing Karen Gillibrand did before announcing her candidacy was to have a round-table with Wall Street executives to fund her campaign.
Bernie has decades of advocacy for civil rights and economic justice that he has rarely, if ever, wavered from. On every topic that is becoming a hot-button issue in the current political climate, you can probably find Bernie supporting the progressive viewpoint years before anybody else was talking about it. Same-sex marriage is a good example of this.
He is not a perfect candidate, but he is the only candidate that isn't an empty suit, an authoritarian, a warmonger, a slave to Wall Street, a center-right pragmatist, or a no-name. It sucks that this is true, but that doesn't make it not true.
